/*
 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package java.util.stream;

/**
 * An enum describing the known shape specializations for stream abstractions.
 * Each will correspond to a specific subinterface of {@link BaseStream}
 * (e.g., {@code REFERENCE} corresponds to {@code Stream}, {@code INT_VALUE}
 * corresponds to {@code IntStream}).  Each may also correspond to
 * specializations of value-handling abstractions such as {@code Spliterator},
 * {@code Consumer}, etc.
 *
 * @apiNote This enum is used by implementations to determine compatibility between streams and
 * operations (i.e., if the output shape of a stream is compatible with the input shape of the next
 * operation).
 *
 * <p>Some APIs require you to specify both a generic type and a stream shape for input or output
 * elements, such as {@link TerminalOp} which has both generic type parameters for its input types,
 * and a getter for the input shape.  When representing primitive streams in this way, the generic
 * type parameter should correspond to the wrapper type for that primitive type.
 * @since 1.8
 */
enum StreamShape {
  /**
   * The shape specialization corresponding to {@code Stream} and elements
   * that are object references.
   */
  REFERENCE,
  /**
   * The shape specialization corresponding to {@code IntStream} and elements
   * that are {@code int} values.
   */
  INT_VALUE,
  /**
   * The shape specialization corresponding to {@code LongStream} and elements
   * that are {@code long} values.
   */
  LONG_VALUE,
  /**
   * The shape specialization corresponding to {@code DoubleStream} and
   * elements that are {@code double} values.
   */
  DOUBLE_VALUE
}
